docs: def extract(self, storage_uris, format='csv', csv_delimiter=',', csv_header=True,
                compress=False, use_cache=True, dialect=None, billing_tier=None):
      """Exports the query results to GCS.
  
      Args:
        storage_uris: the destination URI(s). Can be a single URI or a list.
        format: the format to use for the exported data; one of 'csv', 'json', or 'avro'
            (default 'csv').
        csv_delimiter: for csv exports, the field delimiter to use (default ',').
        csv_header: for csv exports, whether to include an initial header line (default True).
        compress: whether to compress the data on export. Compression is not supported for
            AVRO format (default False).
        use_cache: whether to use cached results or not (default True).
        dialect : {'legacy', 'standard'}, default 'legacy'
            'legacy' : Use BigQuery's legacy SQL dialect.
            'standard' : Use BigQuery's standard SQL (beta), which is
            compliant with the SQL 2011 standard.
        billing_tier: Limits the billing tier for this job. Queries that have resource
            usage beyond this tier will fail (without incurring a charge). If unspecified, this
            will be set to your project default. This can also be used to override your
            project-wide default billing tier on a per-query basis.
      Returns:
        A Job object for the export Job if it was completed successfully; else None.
      Raises:
        An Exception if the query or extract failed.
      """
      return self.results(use_cache=use_cache, dialect=dialect,
                          billing_tier=billing_tier).extract(storage_uris, format=format,
                                                             csv_delimiter=csv_delimiter,
                                                             csv_header=csv_header,
                                                             compress=compress)